U.S. patent application number 12/217271 was filed with the patent office on 2008-11-06 for disposable diaper and process for making the same.
This patent application is currently assigned to UNI-CHARM CORPORATION. Invention is credited to Hideyuki Ishikawa.
Application Number | 20080275420 12/217271 |
Document ID | / |
Family ID | 18665030 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080275420 |
Kind Code |
A1 |
Ishikawa; Hideyuki |
November 6, 2008 |
Disposable diaper and process for making the same
Abstract
A disposable diaper has a covering member adapted to cover a
wearer's crotch and waist regions. The covering member includes an
elastically stretchable first layer and an inelastically
stretchable second layer formed with a plurality of continuous
fibers. The continuous fibers are fixed to the first layer in at
least two bonding zones. The covering member presents a
particularly large value of L/D, a ratio of a length L of each
continuous fiber and a distance D in straight line between each
pair of the adjacent bonding zones.
Inventors: |
Ishikawa; Hideyuki;
(Kagawa-ken, JP) |
Correspondence
Address: |
BUTZEL LONG;IP DOCKETING DEPT
350 SOUTH MAIN STREET, SUITE 300
ANN ARBOR
MI
48104
US
|
Assignee: |
UNI-CHARM CORPORATION
Ehime-ken
JP
|
Family ID: |
18665030 |
Appl. No.: |
12/217271 |
Filed: |
July 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09864836 |
May 24, 2001 |
|
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12217271 |
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Current U.S.
Class: |
604/385.29 ;
29/428 |
Current CPC
Class: |
Y10T 29/49826 20150115;
A61F 13/51456 20130101; A61F 13/51464 20130101 |
Class at
Publication: |
604/385.29 ;
29/428 |
International
Class: |
A61F 13/49 20060101
A61F013/49; B23P 11/00 20060101 B23P011/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2000 |
JP |
2000-160909 |
Claims
1. A disposable diaper comprising: an elastically stretchable
covering member for covering a diaper wearer's crotch and waist
regions; a liquid-pervious sheet having a skin contactable surface
for contacting with skin of said diaper wearer; a liquid-absorbent
core member sandwiched between a said liquid-pervious sheet and
said covering member: discrete elastic members provided along
transverse side edges of said diaper to extend circumferentially
along leg-openings that are defined when the diaper is put on the
diaper wearer; said covering member consisting of an elastically
stretchable first layer and an inelastically stretchable second
layer formed of a plurality of continuous fibers, and said
continuous fibers being fixed to said elastically stretchable first
layer in bonding zones spaced apart from each other so that a ratio
of L.sub.1/D.sub.1, where L.sub.1 is a length of said continuous
fibers extending between a first pair of said bonding zones in a
centrally located first zone on said covering member and D.sub.1 is
a distance in a straight line between said first pair of bonding
zones in said first zone of said covering member is larger than a
ratio of L.sub.2/D.sub.2, where L.sub.2 is a length of said
continuous fibers extending between a second pair of said bonding
zones in a second zone on said covering member and D.sub.2 is a
distance in a straight line between said second pair of bonding
zones in said second zone of said covering member, whereby said
covering member is more easily stretched in a direction away from
the skin contactable surface in said first zone than in said second
zone of said covering member, and said first zone being adjacent
said liquid-absorbent core member and at least substantially
coextensive with said liquid-absorbent core member, so that
pressure exerted on said covering member by said liquid-absorbent
core member will stretch the first zone in said direction of the
skin contactable surface without exerting any pressure on said
discrete elastic members.
2. The diaper according to claim 1, wherein said first zone is a
transversely middle zone of said diaper.
3. The diaper according to claim 1, wherein said elastically
stretchable first layer is formed of an elastically stretchable
film.
4. The diaper according to claim 1, wherein said continuous fibers
of said inelastically stretchable second layer are made of
polypropylene.
5. The diaper according to claim 1, wherein said elastically
stretchable first layer is formed from a liquid-impervious sheet
and lies inside said inelastically stretchable second layer.
6. The diaper according to claim 1, wherein said elastically
stretchable first layer is formed from a liquid-impervious sheet
and lies inside said inelastically stretchable second layer so that
said elastically stretchable first layer functions as a
liquid-impervious backsheet for said liquid-absorbent core
member.
7. A process for making a disposable diaper comprising an
elastically stretchable covering member adapted to cover diaper
wearer's crotch and waist regions and a liquid-absorbent core
member sandwiched between a liquid-pervious sheet destined to come
in contact with skin of said diaper wearer and said covering
member, said process comprising the steps of: bonding an
elastically stretchable first layer destined to form said covering
member and a second layer formed with a plurality of inelastically
stretchable continuous fibers together in a plurality of
intermittently formed bonding zones and thereby to form a composite
sheet, stretching only a portion of said composite sheet in one
direction so that said first layer forming said portion may be
elastically stretched together with said continuous fibers, and
then leaving said composite sheet contract under a contractile
force of said first layer to form said covering member.
8. The diaper according to claim 1, wherein said elastically
stretchable first layer is formed of a nonwoven fabric made of
crimped fibers.
9. The diaper according to claim 1, wherein said continuous fibers
of said inelastically stretchable second layer are made of
propylene copolymers.
10. The diaper according to claim 1, wherein said first zone
presents a stress of 0.25-2 N/25 mm width as said first zone is
stretched by 20%, which is less than 80% if stress presented by
each of said second zones is stretched by 20%, and said
liquid-pervious sheet is stretchable transversely of said diaper as
easily as or more easily than said first zone of said covering
zone.
11. A process for making a disposable diaper having an elastically
stretchable, liquid-impervious covering member for covering a
diaper wear's crotch and waist regions, an elastically stretchable,
liquid-pervious sheet having a skin contactable surface for
contacting with the skin of the diaper wearer, and a
liquid-absorbent core member positioned between said elastically
stretchable, liquid-pervious sheet and said elastically
stretchable, liquid-impervious covering member, said process
comprising the steps of: providing an elastically stretchable,
liquid-impervious first layer from which to form said covering
member, dividing said elastically stretchable, liquid-impervious
first layer transversely into a first zone that will extend in a
transverse middle zone of a disposable diaper made by said process
and a pair of second zones that extend adjacent transversely
opposite sides of said first zone wherein said first zone extends
to vicinities of transversely opposite side edges of a core member
position and to vicinities of longitudinally opposite end edges of
a diaper made by said process; providing an elastically
stretchable, liquid-pervious second layer formed of a plurality of
inelastic stretchable continuous fibers; bonding said elastically
stretchable, liquid-impervious first layer and said elastically
stretchable, liquid-pervious second layer together at a plurality
of intermittently formed bonding zones to thereby form a composite
sheet; stretching only said first zone of said composite sheet in
one direction by at least 50% so that said elastically stretchable,
liquid-impervious first layer in said first zone may be elastically
stretched together with said inelastic stretchable continuous
fibers, while clamping transversely opposite side edges of said
composite sheet so as to prevent said transversely opposite side
edges from stretching; allowing said composite sheet to contract
under a contractible force of said elastically stretchable
liquid-impervious first layer to form said covering member; and
incorporating said covering member into a disposable diaper having
a liquid-absorbent core member so that said stretched and
contracted first zone of said composite sheet is adjacent and at
least substantially coextensive with said liquid-absorbent core
member.
12. The process according to claim 11, wherein said composite sheet
is obtained by discharging said continuous inelastic stretchable
fibers from a plurality of extruding nozzles and accumulating said
extruded fibers onto one surface of an elastically stretchable film
web thereby forming said elastically stretchable first layer, and
thereafter welding said continuous inelastic stretchable fibers and
said elastically stretchable film web together in a plurality of
bonding zones intermediately formed therein.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 09/864,836, filed May 24, 2001 to which
priority is claimed under 35 U.S.C. .sctn.120 and through which
priority is claimed under 35 U.S.C. .sctn.119 to Japanese Priority
Patent Application No. 2000-160909, filed May 30, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a disposable diaper and a process
for making the same.
[0003] Japanese Patent Application Publication No. 1991-162854A
describes pants-type or brief-type undergarments that comprise an
elastically stretchable topsheet, an elastically stretchable
backsheet, elastic members extending along transversely opposite
side edge portions of a crotch region so as to be associated with
leg-openings and elastic members extending longitudinally opposite
end portions of front and rear waist regions so as to be associated
with a waist-opening. A water-absorbent core member may be disposed
between the topsheet and the backsheet to use this undergarment as
a disposable diaper. With such diaper, according to the description
in the Publication, elastic stretchability of the topsheet and the
backsheet serves to offer a good fitness and the sealing effect of
the elastic members associated with the leg-openings serves to
prevent sideways leaking of excretion from occurring along the
leg-openings as the diaper is put on the wearer's body.
[0004] The disposable diaper of prior art enables the topsheet and
the backsheet to be stretched so as to offer good fitness around
the wearer's waist as the diaper is put on the wearer's body.
However, stretching of the topsheet and the backsheet affects the
elastic members associated with the leg-openings and tends to
partially disengage the elastic members from the wearer's legs,
thereby deteriorating the sealing effect of the elastic members. As
a consequence, there is an anxiety that sideways leaking of
excretion might occur along the elastic members associated with the
leg-openings.
SUMMARY OF THE INVENTION
[0005] It is an object of this invention to provide a disposable
diaper designed so that a wearer's crotch and waist regions can be
covered by an elastically stretchable covering member without
deteriorating a desired effect of preventing excretion leakage from
occurring around wearer's legs.
[0006] According to an aspect of this invention, there is provided
a disposable diaper comprising an elastically stretchable covering
member adapted to cover a wearer's crotch and waist regions and a
liquid-absorbent core member sandwiched between a liquid-pervious
sheet destined to come in contact with skin of the diaper wearer
and the covering member.
[0007] According to this invention the covering member consists of
an elastically stretchable first layer and an inelastically
stretchable second layer formed with a plurality of continuous
fibers, the continuous fibers being fixed to the first layer in at
least a pair of bonding zones that are spaced apart from each other
so that a ratio of L.sub.1/D.sub.1, where L.sub.1 is a length of
said continuous fibers extending between a first pair of said
bonding zones in a first zone on said covering member and D.sub.1
is a distance in a straight line between said first pair of bonding
zones in said first zone of said covering member is larger than a
ratio of L.sub.2/D.sub.2, where L.sub.2 is a length of said
continuous fibers extending between a second pair of said bonding
zones in a second zone on said covering member and D.sub.2 is a
distance in a straight line between said second pair of bonding
zones in said second zone of said covering member.
[0008] Another aspect of this invention concerns a process for
making a disposable diaper comprising an elastically stretchable
covering member adapted to cover a diaper wearer's crotch and waist
regions and a liquid-absorbent core member sandwiched between a
liquid-pervious sheet destined to come in contact with skin of the
diaper wearer and the covering member.
[0009] According to this invention the process comprises steps of
bonding an elastically stretchable first layer destined to form the
covering member and a second layer formed with a plurality of
inelastically stretchable continuous fibers together using a
plurality of intermittently formed bonding zones to form a
composite sheet and stretching only a portion of the composite
sheet in one direction so that the first layer of the stretched
portion may be elastically stretched together with the continuous
fibers. After stretching, the composite sheet is allowed to
contract under a contractile force of the first layer to form the
covering member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a plan view of disposable diaper as partially
broken away;
[0011] FIG. 2 is a sectional view taken along a line II-II in FIG.
1;
[0012] FIG. 3 is a sectional view taken along a line III-III in
FIG. 1;
[0013] FIG. 4A is a fragmentary perspective view of the backsheet
taken from range A in FIG. 2;
[0014] FIG. 4B is a fragmentary perspective view of the backsheet
taken from range B in FIG. 2;
[0015] FIG. 5 is a diagram illustrating a process for making the
backsheet;
[0016] FIG. 6 is a view similar to FIG. 1 showing one preferred
embodiment of this invention; and
[0017] FIG. 7 is a sectional view taken along a line VII-VII in
FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Details of the disposable diaper and the process for making
the same according to the present invention will be more fully
understood from the description given hereunder with reference to
the accompanying drawings.
[0019] A disposable diaper 1 shown by FIG. 1 in a plan view as
partially broken away comprises a liquid-pervious topsheet 2, a
liquid-impervious backsheet 3 and a body fluid absorbent core
member 4 disposed between the topsheet 2 and the backsheet 3. The
backsheet 3 is formed with an inside sheet 3a and an outside sheet
3b. The diaper 1 is composed, in its longitudinal direction, of a
front waist region 6, a rear waist region 7 and a crotch region 8
extending between these two waist regions 6, 7. The topsheet 2 and
the backsheet 3 are placed upon one another and bonded to each
other over portions of the topsheet 2 and backsheet 3 that extend
outward beyond a peripheral edge of the core member 4 so as to form
a front flap 11, a rear flap 12 and a pair of side flaps 13 that
are adapted to cover a crotch and a waist of a diaper wearer. The
rear flap 12 has an elastic member 16 extending transversely of the
diaper 1 that is bonded under tension to inner surface of at least
one of the topsheet 2 and the backsheet 3 in order to be associated
with a waist-opening. The side flaps 13 have elastic members 17
that extend longitudinally of the diaper 1 and are bonded under
tension to the inner surface of at least one of the topsheet 2 and
the backsheet 3 in order to be associated with respective
leg-openings. In the rear waist region 7, a pair of tape fasteners
18 are attached to side edge portions of the side flaps 13,
respectively.
[0020] The topsheet 2 is elastically stretchable and may be formed,
for example, from a nonwoven fabric made of elastically stretchable
filaments. The topsheet 2 is elastically stretchable at least
transversely of the diaper 1 and, more preferably, along its length
as well as along its width.
[0021] The inside sheet 3a of the backsheet 3 is liquid-impervious
and formed from a sheet that is elastically stretchable
transversely of the diaper 1 and, more preferably, is elastically
stretchable along its length as well as along its width. The
outside sheet 3b comprises a plurality of inelastically stretchable
continuous fibers 20 (See FIG. 4) accumulated on one surface of the
inside sheet 3a so as to form a sheet and are bonded to the one
surface in a plurality of bonding zones 21 (See FIGS. 4A and
4B).
[0022] FIGS. 2 and 3 are sectional views taken along lines II-II
and III-III in FIG. 1, respectively. In the diaper 1, the backsheet
3 is substantially flat and the core member 4 protrudes from the
backsheet 3 toward the topsheet 2 (downward as viewed in FIGS. 2
and 3). The backsheet 3 is divided at least transversely into a
range A extending in the middle zone and ranges B extending on both
sides of the range A with the range A being more easily stretched
than the ranges B. According to one preferred embodiment, the
transversely middle zone having range A presents a stress of
0.25.about.2 N as measured on a test piece having a width of 25 mm
as this zone A is stretched by 20%. This value is less than 80%,
more preferably less than 50% of a stress presented by each of the
ranges B as they are stretched by 20%. The topsheet 2 is
stretchable transversely of the diaper 1 as easily as or more
easily than the range A of the backsheet 3. The range A extends to
the vicinity of transversely opposite side edges 4a, 4a of the core
member 4 transversely of the diaper 1 and extends substantially
over a full length of the backsheet 3 longitudinally of the diaper
1.
[0023] Only the range A of the backsheet 3 is deformed as indicated
by chain lines in FIG. 2. The core member 4 shifts its position so
as to protrude outwardly of the diaper 1 when the diaper 1 is put
on a wearer's body with the topsheet 2 placed against the wearer's
skin under pressure P exerted on the core member 4 (See FIGS. 2 and
3). The pressure P is adequately dampened by the stretching of the
range A to avoid exerting pressure on the elastic members 17 of the
leg-openings via the ranges B. Thus, there is no apprehension that
the desired fitness of the elastic members 17 around the wearer's
legs might be adversely affected by the pressure P. In this way,
the elastic members 17 associated with the leg-openings cooperate
with the ranges B, which are less stretchable than the range A, so
to maintain the desired fitness of the diaper 1 around the wearer's
legs. It is unnecessary for such diaper 1 to use elastic members 17
associated with the leg-openings that have a relatively high
stretch stress to compensate for the influence of the pressure P.
With such diaper 1 according to the present invention, there is no
anxiety that the elastic members 17 will have a relatively high
stretch stress that might be unacceptably pressed around the
wearer's legs.
[0024] FIG. 4A is a fragmentary perspective view of the backsheet 3
taken from range A in FIG. 2 and FIG. 4B is a fragmentary
perspective view of the backsheet taken from range b in FIG. 2. The
inside sheet 3a has a basis weight of 10.about.100 g/m.sup.2 and is
formed from an elastic material such as styrene-based elastomer or
urethane-based elastomer. The outside sheet 3b has a basis weight
of 8.about.50 g/m.sup.2 and is formed from a sheet-like
accumulation of inelastically stretchable continuous fibers 20 such
as polypropylene, ethylene/propylene copolymer or
ethylene/propylene/butene copolymer fibers. The inside and outside
sheets 3a, 3b are bonded together in bonding zones 21 that are
formed intermittently transversely of the diaper 1, and more
preferably, transversely and longitudinally of the diaper 1. In
these bonding zones 21, the inside and outside sheets 3a, 3b are
bonded together by fusion or adhesion.
[0025] Each of the continuous fibers 20 has a length L and
describes a curve between each pair of the adjacent bonding zones
21, 21 in which the continuous fibers 20 are fixed to the inside
sheet 3a. D designates a distance along a straight line connecting
each pair of the adjacent bonding zones 21, 21. The ratio L/D is
equal to 1 or larger. The ratio L.sub.1/D.sub.1 in the range A of
the backsheet 3 is larger than the ratio L.sub.2/D.sub.2 in the
ranges B (Note: FIGS. 4A and 4B are illustrative only and not drawn
to depict relative proportions and the subscripts "1" and "2" are
used herein to distinguish L and D for each of the ranges A and B).
In other words, the range A is more easily stretchable than the
ranges B transversely as well as longitudinally, at least
transversely of the diaper 1. During an early stage of transversely
stretching the backsheet 3, the inside sheet 3a is elastically
stretched in the range A and the continuous fibers 20 are
reoriented so as to be straightened between the respective pairs of
the adjacent bonding zones 21, 21 in which these continuous fibers
20 are fixed to the inside sheet 3a. So far as the continuous
fibers 20 are merely reoriented and substantially not stretched,
the force required to stretch only the inside sheet 3a is
sufficient to stretch the range A. After the early stretching stage
has been completed and the continuous fibers 20 have been
straightened, a considerable force is required to stretch the
inside sheet 3a together with the outside sheet 3b comprising the
continuous fibers 20 in the range A. On the other hand, in the
ranges B of the backsheet 3 the ratio of L.sub.2/D.sub.2, i.e., a
ratio the length L.sub.2 of the continuous fibers 20 to the
distance D.sub.2 in a straight line between the respective pairs of
the adjacent bonding zones 21, 21 is substantially smaller than the
ratio of L.sub.1/D.sub.1 in the range A and therefore, a
considerable force is required to stretch the inside sheet 3a
together with the outside sheet 3b transversely of the diaper 1
after the early stage of stretching the backsheet 3.
[0026] As has been described above, the topsheet 2 is elastically
stretchable while the backsheet 3 has the range A that requires no
large force to stretch this range and the ranges B that require a
considerable force to stretch these ranges. Accordingly, the
pressure P exerted on the core member 4 by the wearer's body via
the topsheet 2 as the diaper 1 is put on the wearer's body is well
absorbed by stretching of the range A, as indicated by the
imaginary lines in FIGS. 2 and 3. In this manner, there is
substantially no possibility that the pressure P might be exerted
on the ranges B also and affect the elastic members 17 associated
with the leg-openings.
[0027] FIG. 5 is a diagram illustrating a part of the process for
making the backsheet 3. In step I, continuous fibers 220 destined
to form the outside sheet 3b are discharged from a plurality of
extruding nozzles (not illustrated) and accumulated onto one
surface of elastically stretchable web 203a destined to form the
inside sheet 3a of the backsheet 3. Then, a plurality of bonding
zones 221 are intermittently formed in which stretchable web 203a
and continuous fibers 220 are welded together to form composite web
200 which is, in turn, fed from the left as viewed in FIG. 5.
[0028] In step II, transversely opposite side edge regions 231
indicated by oblique lines of the composite web 200 are clamped so
that these side edge portions 231 would not be stretched in the
subsequent steps.
[0029] In step III, a transversely middle region 232 of the
composite web 200 which is free from the clamping effect is
transversely stretched by at least 50% or more, preferably by 80%
or more, and more preferably by 200% or more. In this step III, the
stretchable web 203a is elastically stretched and the continuous
fibers 220 are inelastically stretched between the respective pairs
of the adjacent bonding zones 221, 221, in other words, stretched
under plastic deformation. Along the transversely opposite side
edge regions 231, both the stretchable web 203a and the continuous
fibers 220 are not stretched.
[0030] In step IV, the composite web 200 having been stretched is
contracted under a contractile force of the stretchable web 203a
and thereafter the composite web 200 is unclamped.
[0031] The contracted composite web 200 obtained in the manner as
has been described may be cut into an appropriate length to obtain
the backsheet 3 of FIG. 1 wherein the middle region 232 and the
side edge regions 231 of the composite web 200 define the inside
sheet 3a and the outside sheet 3b of the backsheet 3, respectively.
The continuous fibers 220 and the bonding zones 221 correspond to
the continuous fibers 20 and the bonding zones 21, respectively. In
the backsheet 3 obtained through these steps, the continuous fibers
20 extending within the range A have been stretched at a higher
ratio than the continuous fibers 20 extending in the zones B and
consequently the formers are thinner than the latter. The ratio
L.sub.1/D.sub.1 between each pair of the adjacent bonding zones 21,
21 is larger in the range A than the ratio L.sub.2/D.sub.2 in the
ranges B. The outside sheet 3b comprising the continuous fibers 20
is more bulky in the range A than in the ranges B since the
continuous fibers 20 have been stretched at a higher ratio in the
range A than in the ranges B. The backsheet 3 offers more flexible
and soft touch in the range A than in the ranges B.
[0032] FIG. 6 is a view similar to FIG. 1 showing one preferred
embodiment of this invention and FIG. 7 is a sectional view taken
along a line VII-VII in FIG. 6. The diaper 1 illustrated in FIGS. 6
and 7 has a covering member 40 adapted to cover crotch and waist
regions of the wearer and an absorbent member 45 adapted to absorb
body fluids. The absorbent member 45 comprises a core member 44
lying inside the covering member 40, a liquid-pervious sheet 42
covering the core member 44 and destined to come in contact with
the wearer's skin and a liquid-impervious sheet 43 lying on the
side opposed to the liquid-pervious sheet 42 with the core member
44 therebetween. Both the liquid-pervious sheet 42 and the
liquid-impervious sheet 43 are elastically stretchable preferably
in the transverse direction, and more preferably elastically
stretchable in both the transverse direction and in the
longitudinal direction of the diaper 1. Portions of these sheets
42, 43 extending outward beyond a peripheral edge of the core
member 44 are placed upon each other and are bonded to each other
by means of hot melt adhesive 49. The covering member 40 is
longitudinally composed of a front waist region 46, a rear waist
region 47 and a crotch region 48 extending between the front waist
region 46 and the rear waist region 47. The liquid-impervious sheet
43 longitudinally extending outward beyond the peripheral edge of
the core member 44 is bonded to the inner surface of the covering
member 40 along respective end portions 51, 52 thereof in the front
waist region 46 and the rear waist region 47, also by means of hot
melt adhesive 49. While the portion of the liquid-impervious sheet
43 extending between the end portions 51, 52 has been described to
be bonded to the covering member 40 by means of hot melt adhesive,
it is also possible to leave this portion unbonded to the covering
member 40.
[0033] The covering member 40 comprises an elastically stretchable
liquid-impervious inside sheet 40a and an outside sheet 40b formed
with inelastically stretchable continuous fibers 20. These two
sheets 40a, 40b are bonded together in a plurality of bonding zones
61 formed intermittently in at least in the transverse direction of
the diaper 1. Transverse stretchability of such covering member 40
is substantially similar to that of the backsheet 3 shown in FIGS.
1.about.3. Specifically, the covering member 40 has the range A
defined in the transversely middle zone thereof and the ranges B
defined on both sides of the range A. In the range A, the
continuous fibers 20 have been stretched at a relatively high ratio
so that the covering member 40 can be easily stretched in this
range A. In the ranges B, the continuous fibers 20 substantially
have not been stretched and therefore it is not so easy to stretch
the covering member 40 in these ranges B. Along the end portion 52
of the rear waist region 46, an elastic member 56 associated with
the waist-opening is disposed between the inside sheet 40a and the
outside sheet 40b and bonded to the inner surface of at least one
of these sheets 40a, 40b.
[0034] In the case of this diaper 1 also, the pressure P exerted on
the absorbent member 45 including the core member 44 is
sufficiently absorbed by the range A of the covering member 40,
having been stretched to prevent the pressure P from affecting
elastic members 57 associated with the respective leg-openings. As
a consequence, it is not apprehended that the pressure P applied to
this diaper will cause the members 57 to be disengaged from the
wearer's legs and thereby cause sideways leaking of excretion.
[0035] While this invention has been described hereinabove with
respect to the open-type diaper 1 as a typical embodiment, this
invention is also applicable to a pants-type diaper. It is not
essential to define the range A of the member covering the crotch
and waist regions in which this member is more easily stretchable
than the remaining zones in the transversely middle zone of the
member, since the range in which this member is more easily
stretchable than the remaining zones may be selectively defined in
any desired zone.
[0036] In the disposable diaper according to this invention, the
covering member adapted to cover the crotch and the waist regions
is formed so that the covering member can be more easily stretched
in its transversely middle zone than in its transversely opposite
side edge portions. With this unique arrangement, the pressure
exerted from the wearer's body upon the absorbent core member as
the diaper is put on the wearer's body is substantially prevented
from affecting the elastic members associated with the
leg-openings. In this way, it is possible to eliminate an anxiety
that the elastic members might be disengaged from the legs and, as
a result, excretion might leak sideways.
* * * * *